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JEWELED BEARINGS 

FOR 

WATCHES 



A FULL AND COMPLETE DESCRIPTION OF THE MANUFACTURE, 

GAUGING AND SETTING OF JEWELED BEARINGS IN 

TIMEKEEPING INSTRUMENTS 



By CHARLES T. HIGGINBOTHAM 

CONSULTING SUPERINTENDENT SOUTH BEND WATCH COMPANY 

And PAUL HIGGINBOTHAM 



CHICAGO: 

HAZLITT & WALKER, PUBLISHERS 
1911 



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Copyright, 1311, Hazlitt & Walker. 






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JEWELED BEARINGS FOR WATCHES. 




c There has been no single improvement in watch manufac- 
turing of so great a value to time keeping as the jeweled 
bearing, which has universally superceded the brass and 
gold plugs, or bushings which were formerly used and 
which were found very unsatisfactory because of friction, 
wear and corrosion. The honor of being the first to use 
gems — jeweled bearings — for watches is due to an Italian, 
Nicholas Facio, who after prolonged experiments and re- 
peated failures finally succeeded, about the year 1723, in 
successfully applying them to watches, although the reader 
must not imagine that they bore any similarity to the watch 
jewel of today other than that the material was the same. 

Instead of a hole piercing the jewel there was ground in 
one face a V-shaped depression (See Fig. 1) which made it 
extremely difficult to finish because of the tendency to form 
a tit at the bottom of the depression during the operation ; 
furthermore such a shape was only suitable for V-shaped 
pivots such as are now found only in cheap clock move- 
ments. Nor must the reader imagine that the art of cutting 
precious stones was previously unknown, nor that up to the 
time of Facio, jewels had not been drilled, for such was not 
the case. Cutting gems had been extensively done and 
there is a record of a Roman architect, Vitruvius, who about 
the year 250 B. C. constructed a clepsydra in which was 
used a drilled jewel for the opening through which water, 
by which it was actuated, found egress. 

Although the Swiss were quick to realize the advantages 
to be secured by jewelled bearings and began experimenting 
on their manufacture, the difficulty of making and polishing 

3 



JEWELED BEARINGS FOR WATCHES. 




Figure 1. 



JEWELED BEARINGS FOR WATCHES. 5 

a V-shaped depression without leaving, either a tit, or a flat 
bottom was very great, in fact practically insurmountable, 
so that not until about a century later did jewels for watches 
come into general use, and even then, only for the balance 
and escapement pivots. By this time the pierced jewel 
had superceded the V cup. The process of drilling and 
shaping such minute openings as are required for watch 
pivots was entirely new and was fraught with many diffi- 
culties. These difficulties required a long time to over- 
come, so that as late as the present century many great im- 
provements in the method of manufacture have been made. 

There are practically but four kinds of jewels used in 
the watches of today ; namely, diamonds, sapphires, rubies 
and garnets, although aquamarine and chrysolite have been, 
and are now, used to some extent. What is known as dia- 
mond chips are used almost universally as upper and lower 
cap jewels for marine chronometers, and are growing in 
popularity with the makers of fine watches both in this 
country and abroad. The Swiss, however, have in many so- 
called 'imitation jeweled watches" used diamond cap jewels 
for the upper alone, with a ruby or other stone for the lower, 
which together with the practice of jeweling only the upper 
train holes have won for them the name, "Imitation 
Jeweled." This practice has been carried to a still greater 
extent, in the custom of inserting garnet, and even glass 
endstones into recesses in the top plates where actually no 
pivots found bearings. 

The balance of a marine chronometer being of consid- 
erable weight, and the instrument being run in such a posi- 
tion that the entire weight is sustained by the end of one 
of the staff pivots, this pivot is found very apt to wear a 
depression in any stone, even a diamond ; and the moment 
this wearing or cutting begins, it goes on very rapidly, for 
the reason that the end of the pivot quickly becomes charged 
with particles of the stone ; in fact when a diamond end- 
stone begins to pit it cuts more rapidly than a sapphire. The 
pitting of endstones (commonly attributed to soft, spongy, 



O JEWELED BEARINGS FOR WATCHES. 

or imperfect jewels) more frequently comes from quite 
another cause. At the time machine made balance staffs 
were introduced, the belief prevailed that the method of 
grinding the pivots with diamond laps charged the pivot 
end and was responsible to a great extent for pitted end- 
stones. It has been demonstrated, however, that this is an 
error. Grinding a pivot which is properly tempered, with 
a diamond lap will never charge it. The writer has by 
extensive experiments and exhaustive tests proved to his 
own entire satisfaction that the main cause for pitted end- 
stones is from improper hardening and tempering of the 
steel of which they are composed. It is a well known fact 
that diamond is crystalized carbon. Now when high carbon 
steel such as is used for balance pivots is overheated in 
hardening, the carbon which it contains becomes crystalized 
and forms minute particles that, if not actual diamonds, 
possess all the abrasive properties of the diamond itself, 
and will cut any stone, even a diamond. In experimenting 
along this line it was found that a stafT made of steel rich 
in carbon, when heated to a white heat in hardening would 
cut an endstone in 24 hours. The same steel heated to blood 
red in hardening would not do so. The experiment was also 
tried of reheating a staff several times, the result being that 
as the carbon was more or less burnt out by repeated heat- 
ing, the pivot became less and less liable to pit the stone. 

The sapphire, we might say is, almost without excep- 
tion, used for barrel arbor, or main wheel and for center 
lower jewels and is exceptionally well adapted for this use 
because of its superior strength and its minimum cost for 
stones of this size. It is also used for balance hole jewels 
and for cap jewels. Sapphires and light rubies are almost 
indistinguishable from each other, and are used indiscrim- 
inately, except in watches where the display of a higher 
colored stone for the upper endstone is desired, in which 
case the high colored ruby, known as the pigeon blood, re- 
places the sapphire, although it is a softer stone. Since the 
introduction and popularity of the double roller and steel 



JEWELED BEARINGS FOR WATCHES. J 

escape wheel, sapphire roller pins — impulse pins — are used 
because of their superior strength, and sapphire pallet stones 
because the steel wheel will not cut that stone. In this con- 
nection let me say that a brass escape wheel tooth when acted 
upon by a sapphire pallet stone is extremely liable to cut, 
whereas, the same tooth acted upon by garnet, will not. 
Sapphire is aluminum colored with titanium and iron while 
ruby is aluminum colored with chromium, thus although 
they are nearly similar, there seems to be a chemical action 
set up when brass escape wheels are used with sapphire, 
also like action (though not so pronounced) when used 
with rubies ; this is made apparent by causing excessive fric- 
tion on the brass wheel, often cutting it quite rapidly and 
sometimes stopping the watch. 

There are several sources of supply for the rough sap- 
phires from which the jewels are cut, chief of which are 
Ceylon, Australia and Montana. They are found in about 
all colors of the rainbow. The Australian stone is the hard- 
est and correspondingly brittle. The stone from Ceylon is 
not quite so hard, and is less brittle. The Montana stone is 
said to be best for jewels in mechanisms where any strength 
is required, as it is less brittle than the others, and therefore 
not so easily fractured. The stones commonly range in size 
from a diameter of about one-quarter inch to three-eighths 
inch. 

The ruby besides being used for balance holes and end- 
stones as above described, is well adapted for upper and 
lower plate holes, the high color — to make a distinction — 
being placed above the center, third, fourth, escape and pal- 
let arbor, except in cases where some of these may be 
capped, or, as in the case with balance jewels, they may, in 
the lighter color, be of the sapphire family. Jewel pins are 
frequently made of ruby for higher grade watches, although 
ruby is not quite as hard. They are frequently used in high- 
grade watches for pallet stones on account of their beauty 
of color. The high-colored ruby is falling into disuse of 
late, for the reason that they are too soft to be satisfactory. 



8 JEWELED BEARINGS FOR WATCHES. 

The garnet is of good color but very soft as compared 
with ruby or sapphire. It is used principally for plate holes 
in third, fourth, escape and pallets, but although it is less 
expensive, both in the rough and to manufacture, it is grow- 
ing less popular every day, at least among American watch 
manufacturers ; and is now principally confined to cheap 
watches. Garnets are much more friable than sapphires 
or rubies and for this reason entail a larger percentage of 
waste during the processes of manufacture, particularly in 
that of setting. Setting in recent years is done largely by 
automatic machines which not being endowed with that 
human quality called judgment, press just as hard on a thin 
jewel as a thick one. Garnets are, however, peculiarly adap- 
ted for use as pallet stones in connection with brass wheels, 
and in this connection are used almost exclusively. 

Jewel Making. — The requisite equipment for making a 
jewel consists mainly of tools found on the watchmaker's 
bench, together with a few others which are quite simple in 
construction. The lathe may be of any style, but must run 
true and be capable of high speed — say two thousand revo- 
lutions per minute. It should be equipped with a T-rest, a 
female taper chuck, together with a number of brass tapers 
to fit, a copper lap about 4 inches in diameter, an alcohol 
lamp, or a small Bunsen burner to which gas may be led by 
means of a rubber tube ; also the following which it will be 
necessary to make: a diamond drill, a diamond cutter and a 
skive or jewel saw. 

To make the drill, select a slender diamond splint taper- 
ing to a fine point ; of course, only diamond chips or imper- 
fect stones are used for this purpose. All diamonds used 
for this purpose are not of like value ; those of dingy color 
usually make the best drills and cutters, the clear stones, 
while being very hard, are apt to be too brittle for this pur- 
pose. When a workman has secured a drill of the proper 
size, shape and quality, it becomes practically priceless. To 
make a diamond drill, drill into the end of one of the brass 
tapers a hole just large enough to take the splint and secure 



JEWELED BEARINGS FOR WATCHES. 



it by burnishing the soft brass against it. In addition to 
this the space between the diamond and taper may be filled 
with either soft, or hard solder. It is perfectly safe to apply 
any heat that can be developed by a blow pipe to a diamond. 
After being secured to place, the superfluous metal may be 
cut away. To give it the proper length and facilitate its 
manipulation, set the brass taper in a wood handle of any 
convenient size or shape. The cutter for turning the jewel 
is made in the same way, except that the splint is selected 




Fig. 2. 

with a view of having a strong, somewhat chisel-shaped cut- 
ting edge. The skives used in factories are of large di- 
ameter, ten inches or more and are mounted in gangs, the 
individual skives being separated by discs of proper thick- 
ness, according to the jewel desired and that portion pro- 
jecting beyond the flange is sometimes slightly dished. The 
described skives, of course, would be an impossibility on a 
small bench lathe, but for making one or two jewels, the 
lesser diameter will answer. The smaller tool will require 



IO JEWELED BEARINGS FOR WATCHES. 

more frequent charging. To make this, cut from a thin 
sheet of tin a piece, approximately round and of as large 
diameter as will swing in the lathe ; drill a hole in the center 
of the proper size to make a fit on the saw arbor. Now make 
in the same way two discs an inch less in diameter than the 
tin ; these may be either brass or iron and should be of suffi- 
cient thickness to give rigidity to the saw. Clamp these on 
the arbor with the saw between, making sure that it is true 
both as to flat and diameter. See Fig. 2. 

To charge the lap, select a small hard pebble and while 
holding it to the edge of the skive apply drop by drop, 
diamond powder between them while revolving the skive 
slowly. As the skive charges it will cut the pebble more 
and more rapidly, but this may be obviated by applying dif- 
ferent parts of the pebble. Another method is by using a 
roll of hard steel mounted to revolve freely in a suitable 
handle. This is brought against the edge of the skive with 
diamond powder applied between. The diamond powder 
used for this purpose may be quite coarse. No. 1 is none 
too fine. The copper lap may be charged by hammering 
the diamond powder into its face, but a more economical 
way is that of rolling in as has been described for the skive. 

The tools are now ready to begin operations, but first we 
will describe the preparation of diamond powder, for 
although few watch repairers use it in sufficient quantity to 
make it practical from an economical standpoint to settle 
their own, still it is well to know how it is done. Diamond 
powder is made from diamond borts, or splints, by pounding 
them with a steel pestle in a steel mortar. The mortar is 
fitted with a steel cover which is usually threaded to screw 
into the mortar. Through the center of the cover a hole is 
made large enough to admit the pestle which is packed or 
surrounded with sheet rubber to prevent any of the small 
particles of diamond from being lost during the operation. 
See Figs. 3 and 4. 

The diamond is broken into minute particles by striking 
the upper end _of the pestle with a hammer. This is ron- 



JEWELED BEARINGS FOR WATCHES. 



II 



tinued until the proper degree of fineness is reached which 
can be determined by frequently testing between the fingers. 
Considerable practice will be required to know when it has 
been ground enough, though it can hardly be ground too 





Fig. 4. 



much, except that the longer it is ground, the more of the 
finer grades and the less of the coarser will be the result. 
After crushing sufficiently, empty the powder on a large 
sheet of fine surfaced white paper, taking care to gather all 



12 



JEWELED BEARINGS FOR WATCHES. 



the dust and particles. Having previously secured a half 
dozen bowls with straight sides and rounded corners at the 
bottom, for the purpose of insuring a uniform settling and 
of facilitating the removal of the powder when settled (see 
Fig. 5) fill a bowl with oil. Olive oil is frequently used for 
this purpose, but I prefer clock or watch oil for the reason 
that it can be used over and over again without becoming 
rancid, whereas in using olive oil fermentation is likely to 
ensue, causing more or less waste of diamond powder. Stif 




Fig. 5. 



the ground powder into the bowl of oil. Allow it to settle 
for about 30 minutes and then pour oft the top ; which is to 
say all but the settlings, into one of the other bowls. Stir 
thoroughly that portion which has just been poured off and 
allow it to settle for an hour. Repeat as before and so on 
until there are five different settlings, the first and second 
having been 30 and 60 minutes respectively. The third 
should be allowed to settle four hours, the fourth ten hours 
and the fifth, not less than 24 hours, but preferably a num- 
ber of days. The periods used for settling are varied from 
more or less, depending upon special requirements and spe- 
cial conditions of the oil used. 



JEWELED BEARINGS FOR WATCHES. 13 

The first, or No. i, is the coarse or grinding powder, and 
the last, or No. 5, is the polishing powder. In watch fac- 
tories No. 1 is used on laps, chiefly for grinding steel tools 
and watch parts, but for the ordinary watch bench, it would 
be well to continue the grinding of the powder in order to 
produce by far the largest per cent of No. 3, No. 4 and No. 
5, No. 1 may be used for charging skives and laps as well 
as sharpening tools. In this connection let me say that the 
charged lap will be found an excellent and expeditious 
method for sharpening drills and other tools. The second, 
or No. 2, may be used on laps for grinding jewels and No. 
3 on laps for polishing. No. 4 and No. 5 are used on laps 
usually of ivory, celluloid, African box-wood, tortoise shell 
and other substances. These laps are not charged, but have 
the diamond powder placed loosely upon them. 




Fig. 6. 

It sometimes happens that, after settling the powder, it 
has not been sufficiently crushed to give the proper grades, 
in which case cut the oil by adding benzine and after settling 
for five or six hours, pour ofT the top. This should be re- 
peated and then the residue allowed to evaporate. The pow- 
der can then be placed in the mortar and reground. 

Jewel Making by tfie English Process. — The old 
English method of jewel making is as follows : The pebble 
from which it is desired to make the jewel is cemented on 
the end of a stick about 8 or 10 inches in length, shaped on 
one end to make it convenient to hold in the hand and taper- 
ing to the other end to approximately the diameter of the 
pebble. Place the skive in the lathe, adjusting the T-rest 
close to it, somewhat below the center and set the lathe in 



14 JEWELED BEARINGS FOR WATCHES. 

motion. The speed for a skive may be varied considerable. 
For ordinary use two thousand revolutions will be found to 
answer the purpose very well, but after some practice this 
speed may be increased considerably. Steadying the stick 
against the T rest, hold the jewel with a light pressure 
against the skive edge as illustrated, Fig. 6. 




During the operation of cutting, in order to prevent over- 
heating, oil should be frequently applied. This may be 
readily accomplished by suspending a sponge saturated with 
oil, on a piece of wire above the skive, so that it will come 
in contact with the edge. Make as many slots parallel to 
each other as the size of the pebble and the thickness of the 
jewels will allow, taking care that the distances between the 
slots — the thicknesses of the slabs — is somewhat greater 



JEWELED BEARINGS FOR WATCHES. 



15 



than the thickness the jewel is to be when finished. When 
flaws are sawed into, or the slab is not flat the defective 
slabs may be saved frequently by lapping them down as illus- 
trated. This is seldom advisable except for special jewels. 
Remove the slabs, clean the cement from them and mark 
off on one of them a number of squares large enough to 
allow for the diameter of the jewel, Fig. 7. 

These squares may be laid out with a straight edge and 
deeply scratched with a diamond point. They may be broken 




Fig 1 . 7. 



apart by the use of a pair of pliers padded with some soft 
metal. Now take one of these squares and chip off the cor- 
ners with pliers until it is approximately round in shape. 
Place a brass taper in the lathe and true the end, cupping it 
slightly and turning the diameter to somewhat less than the 
finished diameter of the jewel. See Fig. 8. This figure 
shows the end of the taper which it is observed is turned 
to somewhat smaller diameter a short distance back, at A. 



i6 



JEWELED BEARINGS FOR WATCHES. 



The object of this is to facilitate the heating of the end of 
the taper. 

Let the lathe revolve slowly, at the same time heating the 
end of the brass taper by means of the alcohol lamp or Bun- 




Fig. 8. 

sen burner, until it is warm enough to melt shellac, which 
should be applied in a thin layer. Stop the lathe, and quickly 
—before the shellac has had time to cool and set — pick up 
the slab by pressing the end of a finger on it and apply it to 
the end of the taper. Start the lathe slowly, applying gentle 



A 




Fig. 9. 



heat, and with a piece of pegwood touch lightly the outside 
diameter of the jewel until it runs true. Stop the lathe and 
press firmly with the pegwood against the face of the jewel 
until the shellac sets, which will take but a minute; then, 



JEWELED BEARINGS FOR WATCHES. 



17 



with the diamond cutter, turn the outside diameter to the 
size intended for the finished jewel ; then give a slight bevel 
from the front face to form the setting edge, as at A, Fig. 9. 
The jewel is now ready for the drilling operation which 
will probably be attended with much difficulty and many 
spoiled jewels and broken splints, for it is no mean trick to 





sS. 




Fig. 10. 

drill without forming a tit at the bottom of the hole. The 
hole should be drilled a trifle more than half through the 
jewel. When this has been done, remove the jewel and 
reversing it, cement the drilled side to the chuck or taper, 
being careful that it is trued up perfectly, this being abso- 
lutely necessary in order that the holes, drilled from oppo- 



1 8 JEWELED BEARINGS EOR WATCHES. 

site sides, may meet perfectly. Drill as before, but very 
slowly and carefully as the drilling from the other side is 
approached, for then is the greatest danger of breaking 
both drill and jewel. Fig. 10 will illustrate the condition 
sought to be secured in drilling from opposite sides. A is 
a jewel drilled correctly; B is one in which the drillings 
from opposite sides do not coincide. When a rough jewel 
is drilled as shown at B, it is well nigh impossible to secure 
a straight, or round hole by opening, for the reason that the 
wire opener will be more or less deflected as shown at C. 

Before removing the jewel turn the convex curve of the 
outside, also the concave recess or oil cup. Polish and finish 
as follows : Turn a hollow in one end of a copper wire ; 
form a rounded end on a piece of steel wire of the shape 
the outside of the jewel is intended to be — it is not necessary 
to harden the steel — drive the rounded end into the recess 
formed in the copper wire, thus securing the proper shape. 
Putting a little No. 3 diamond powder in the recess thus 
formed, bring it against the jewel and start the lathe run- 
ning. Keep the copper wire constantly moving from side 
to side, the outer end forming an ellipse, frequently moisten- 
ing it with oil in order to prevent heating. It may be 
necessary to add a little more diamond powder once or twice 
during the operation. The object of keeping the copper 
wire in constant motion is that the lines may be broken and 
a uniform surface free from rings be produced. 

This should produce a very fine surface, almost amount- 
ing to a polish. Where a finer polish is desired it may be 
secured by turning a recess in the end of a small strip of 
African boxwood. Putting a little No. 5 diamond powder 
in the recess thus formed, bring it against the jewel and pro- 
ceed as with the copper wire. 

The oil cup is polished in the same way, except that the 
end of the wire, as well as that of boxwood, must be formed 
convex instead of concave. This will leave the circle where 
the concave cup and convex edge meet, sharp and somewhat 
ragged. Flatten this edge slightly with a strip of soft steel 



JEWELED BEARINGS FOR WATCHES. 



19 



charged with No. 3 diamond powder ; then polish it with a 
r trip of boxwood and No. 5 powder. Now remove the 
jewel from the chuck and remove the shellac with alcohol. 
It is now ready for polishing the flat surface, which is best 
done by holding the jewel against the face of a lap with a 
light pressure of the finger. A boxwood lap is best for this 
purpose, and No. 3 diamond powder may be used, except 
where a higher finish is desired which can be secured by an 
additional operation — a boxwood or pine lap with No. 5 
powder. Keep the jewel constantly moving while, being 
presented to the lap. This precaution is necessary in order 
to produce a polish free from lines. 




Fig. 11. 

Opening and Polishing the Hole. — It now remains to 
open the hole to the required size and to give it the proper 
form. This operation may be performed either before or 
after the jewel is set. The advantage of doing this after 
the jewel is set is that it is more readily held in a chuck. 
The disadvantage is that there is more or less danger of 
small particles of diamond powder used in opening, finding 
lodgment between the jewel and its setting, with the danger 
of its ultimately finding its way into the jewel hole. When- 
ever a balance hole is set before opening, it should always 
be removed and reset afterward. In removing the jewel, 
the setting mav be dissolved off with muriatic acid which 



20 JEWELED BEARINGS FOR WATCHES. 

will not injure a sapphire or ruby jewel. A jewel may be 
opened before being set by observing the following direc- 
tions : Take another taper and in the end of it turn a re- 
cess a trifle smaller than the diameter of the jewel, to a 
depth of about the thickness of the jewel'. Saw two longi- 
tudinal slots at right angles to each other through the center 
of the taper, running back about half an inch. Fig. n. This 
forms a spring chuck into which the jewel is pressed and 
will hold it, if carefully made true. 

The opening of a sapphire or ruby jewel is best done with 
a soft steel wire which should be filed to a slight taper. The 
less the taper the better. This may be charged by placing 
diamond powder on a hard steel surface and rolling the 
opening wire on it by means of another hard steel surface. 
This is to say, roll the opener between the two surfaces. In 




Fig. 12. 

using this opener, soap is better than oil as a lubricant. A 
small piece of soap kept moist with water should be at hand 
and the opening wire drawn through it from time to time. 
An opening lathe should run at a speed of not less than two 
thousand revolutions per minute. In using the opener, it 
should be inserted in the hole at a slight angle and a con- 
tinual (but very slight) side to side motion of the wire used. 
Care should be exercised to avoid pressing the wire tightly 
into the jewel being treated, as this is apt to result in a 
broken jewel. When an olive hole is desired, the angle at 
which the opener is entered should be greater than when 
the hole is to be straight. It is also well when opening for 
an olive hole to reverse the jewel in the chuck from time to 
time. The difference between an olive hole and a straight 
hole is shown in Fig. 12, where A is a straight hole and B 
an olive hole. It is a common impression that an olive hole 
creates less friction than a straight one, but this is an error. 
The length of a bearing has nothing to do with frictions. 



JEWELED BEARINGS FOR WATCHES. 21 

The resistance caused by friction, as applied to a balance 
pivot, is determined by the weight of the balance and the 
distance of the surface in contact from the center (the 
diameter of the pivot) and is entirely independent of the 
amount of surface in contact. The advantage of an olive 
hole is that when oiled there is less adhesion of oil between 
the inner wall of the jewel hole and the pivot. If a balance 
could be run without the use of lubricants it would revolve 
just as freely when its pivots had their bearings in a straight, 
as when in an olive hole. Fig. 12 shows the difference be- 
tween straight and olive. A is a straight hole, B an olive. 
The usual range of watch jewel sizes runs from 1 to 3 
millimeters outside diameter, the holes for the pivots rang- 
ing in the different sizes, say from 7/100 to 40/100 milli- 
meters, or, from about 0.003 to 0.016 inch. 




Fig. 13. 

After the jewel has been properly shaped by the opener, 
it should be polished. The polishing is most frequently done 
with a long, pointed piece of pegwood which has been rolled 
in No. 5 powder. Sometimes a slim, pointed piece of tor- 
toise shell is used for a polisher, but a still better one is made 
by dressing a piece of goose quill to a long, slender taper. 
This material is extremely tough and flexible ; hence, its 



22 JEWELED BEARINGS FOR WATCHES. 

superiority. For olive holes, I do not know of its equal. 
When presented to the jewel at an angle, its flexibility causes 
the inner as well as the outer part to lie against the curved 
margin of the hole, producing as near a perfect polish as 
can be secured. I recommend this especially in treating 
balance jewels for adjusted watches. 

For opening holes in softer jewels, such as garnets, a cop- 
per wire is quite as good, possibly better, than a steel one. 
In this case it is not necessary to charge the wire. No. 4 
diamond powder may be used by simply applying it to the 
opener, which charges itself when brought in contact with 
the jewel hole. 

When the jewel hole has been opened and polished, there 
remain two final operations ; that of chamfering both front 
and back. The chamfering is done with a copper wire, the 
end of which should be cone shaped. No. 4 diamond powder 
is best for the purpose. The object to be secured is to form 
a slight chamfer in order to take off the sharp edge where 
the hole and surface meet. Great care should be exercised 
in treating the inner or flat side of the jewel, for the reason 
that if the chamfer is too deep it may allow the chamfer 
usually made on a staff to enter, thus increasing friction. 

JEWEL MAKING ACCORDING TO THE SWISS PROCESS. 

The Swiss method of jewel making differs in many par- 
ticulars from the English method. In cutting the rough 
stone into slabs it is cemented to a short strip of leather. 
This leather is held on a table directly under the skive ; 
the table being moveable upward. It is thus brought against 
the under edge of the skive, the leather being moved along 
as siab after slab is cut. Each slab is then cemented to the 
leather and passed along under the skive, cutting it into 
strips. These strips are broken into smaller pieces and 
brought to an appropriately round shape by chipping the 
edges. In doing this chipping, the stone is laid on a flat 
surface and the edge chipped off with a hard, angular point- 
ed instrument. The stone is then cemented to the chuck in 
a manner similar to that used by the English and the sim- 



JEWELED BEARINGS FOR WATCHES. 23 

ilar operations carried on until the process of drilling is 
reached. Here is the main difference between the English 
and Swiss methods. 

As has been explained, the English pierce the jewel with 
a diamond splint, piercing from both sides, whereas the 
Swiss drill with a steel drill, penetrating the jewel com- 
pletely in one operation. The drill has its end charged, usu- 
ally with very coarse diamond powder. It is made quite 
short to guard against deflection. The lathe is run at a very 
high speed and the drill is also carried by a spindle running 
at a high speed, but in the opposite direction from the lathe. 
This method is a much quicker one than the English splint 
drilling. In using the wire drill it is rarely necessary to 
drill entirely through the jewel. When the drill nears the 
inner face, the operative, with a sharp thrust, breaks out the 
remaining stock, the jagged depression left being shaped 
when the cup is made. The jewel is now cemented on the 
reverse side and the subsequent operations performed in a 
similar manner to the English method. Ordinary sizes of 
jewels are regularly turned, drilled and polished at the rate 
of 80 to 100 in a day. The holes in these jewels can be 
drilled and polished by one operator at the rate of 200 per 
day. 

Inspecting. — American watch manufacturers import 
nearly all their jewels, either direct or through a jobber. 
If imported direct, they have arrangements with the maker 
whereby they return, after examination, all jewels of faulty 
construction or poor material. In fact this is the general 
practice, even when purchased through the medium of a 
jobber or importer. The jewels thus rejected are generally 
placed upon the market at considerably reduced prices. They 
belong in the same category as imitation American watch 
material, and are to be avoided by workmen who take pride 
in their work and desire the best results. 

The inspection in American watch factories is usually 
conducted as follows: A number of jewels, from one hun- 
dred up, in proportion to the number comprising the lot 



24 JEWELED BEARINGS FOR WATCHES. 

being inspected, are examined minutely in every particular. 
Should more than three or four defective jewels be found, 
the entire lot is returned, but in any event each individual 
jewel is inspected. After being inspected, those accepted 
are put through a series of sieves, each having a number 
of holes. These holes are of a uniform diameter in each 
sieve, but diminish by gradations, the uppermost sieve hav- 
ing the largest holes, the difference between the sizes being 
i/iooo of an inch. The sizes embraced by these sieves de- 
termine the limit of sizes to be accepted. Such jewels as 
will not pass through the uppermost sieve, and such sizes as 
do pass through the lowermost are rejected. Those which 
are within the limits are kept separate as to sizes, to facili- 
tate setting. This is absolutely necessary where automatic 
machines are used for the process. 

It is well that the repairer should understand what con- 
stitutes a good jewel. 

The stock, that is the stone itself, should be perfectly 
uniform in color and free from flaws, air bubbles, or other 
defects of that character, its texture showing the character- 
istic uniformity of a perfect stone. The setting edge should 
be thick enough to give a firm hold when the stock is bur- 
nished over it. An excessively thin edge is exceedingly 
liable to fracture in the process of setting. How often a 
jewel is found set in a watch, showing chips in the outer 
edge ! This is the result of a thin edge, or poor workman- 
ship in setting. The edge should be of a uniform thick- 
ness all round. Otherwise it will not be possible to set it 
flat. Another condition as to shape is the convex side. This 
is practically an arc of a circle. If the radius of this arc is 
too small, the jewel will be, so to speak, bullet shaped, and 
inasmuch as this curved surface must rest against a shoulder 
of the setting when the jewel is burnished in, it will be seen 
that it would be very difficult to burnish in a jewel so shaped 
and yet have the face perfectly flat and true with the setting. 
Some jewel setters prefer to have the edge slightly tapered, 
while others prefer it straight — at a right angle with the 



JEWELED BEARINGS FOR WATCHES. 



25 



face, but this is solely a matter of choice, which does not 
affect the excellence of the jewel. Another point to observe 
is that the hole shall be vertical with the flat face of the 
jewel. Where this condition does not exist it is technically 
called an "out of straight hole." Fig. 14. 

In this figure the condition is somewhat exaggerated, it 
being so done to make the nature of the defect clear. Some- 
times this defect is not discovered until the gaging of the 
hole size is being done, when it is found that the jewel will 
tilt to one side. Finally the jewel is inspected for exterior 




Fig. 14. 

finish, finish of the hole, shape of the hole and its chamfer- 
ing. A jewel hole should be either perfectly straight, or 
more or less olive shaped. The difference between straight 
and olive has been previously explained. An olive-shaped 
hole will allow of a closer side shake than a straight one for 
the reason that the least want of conformity between the 
pivot and jewel will make a great difference where a 
straight hole is used. The pivot and the sides of the hole 
must be absolutely parallel where a close side shake prevails 
in a straight hole, and even then the adhesion of oil proves a 
serious drawback. Fig. 15. This figure shows two jewels 
in connection with two pivots identical in size. It will be 
seen that the pivot fitted to the straight hole cannot be tilted 
to the same extent as that fitted to the olive hole, without 
binding. What is known as a "thin hole" is another fault 
often found in jewels. The term, thin hole, does not in 
reality pertain to thickness, but to length, as will be seen 
by comparing jewel A with jewel B, in Fig. 16. In a bal- 
ance jewel a thin hole is a serious fault, frequently resulting 
in the cutting of the balance pivot. 



26 



JEWELED BEARINGS EOR WATCHES. 



Holes out of center — not central with the outside of the 
jewel — are extremely common and sometimes cause much 
trouble. This defect in a jewel itself, provided no other 
one accompanies it, can be remedied by what is known as 





Fig. 15. 



"shellac truing," which will be described later on. Chipped 
holes are apt to be very disastrous, but may be readily dis- 
covered. By chipped holes is meant that a portion of the 
face of a jewel is broken away into the hole, which will 
sometimes cut the shoulder of the pivot. 



JEWELED BEARINGS FOR WATCHES. 



27 



Still another defect is known as "ringed face." Where 
this defect exists, scratches, more or less deep, surround the 
hole. It is usually caused by the point of the opener striking 
the face during the process of opening. 

Finally, in the matter of inspection, the countersink, par- 
ticularly at the face of the jewel, is carefully examined. 
This countersink should be just sufficient to take out the 





Fig. 16. 



sharp edge and such minute chips as may be occasioned by 
the process of making and opening. The expressions, 
making and opening, are used for the reason that they indi- 
cate two entirely different operations. The countersink is 
sometimes extended in order to cut out larger chips ; this 
is a very bad practice. It gives a smaller bearing for the 
pivot shoulder, in some cases even letting the beveled por- 
tion of the staff down •into the countersink, thus causing a 
wedging pressure which is, of course, disastrous to time- 
keeping. 

Fig. 17 shows a train jewel and a balance jewel, both of 
correct shape in every respect. A jewel so shaped may be 
readily set and will produce superior results as to friction, 
retention of oil, etc. 



28 



JEWELED BEARINGS FOR WATCHES. 



Before leaving the subject of jewel inspection, it is well 
to say a few words about stratification. Stratification refers 
to what may be termed the grain of the stone. All precious 
stones, even the diamond, are formed in crystalline layers. 
They have a grain like wood, although this is not apparent 





Fig. 17. 

to the ordinary observer, even under a magnifying glass. 
The diamond cutter, however, frequently acquires a keen- 
ness of observation which will enable him to detect it. This 
is of great assistance to him in his business, inasmuch as it 
is necessary to present a diamond to the lap with its line of 




Fig. 18. 

cleavage (grain) parallel with the circle described by the 
lap in running. In watch jewels the lines of cleavage are 
sometimes, though not as a rule, perceptible. When they 
form an angle with the flat face of an endstone, the angular 
portions of these lines will sometimes chip off in minute par- 
ticles, thus charging the pivot. Fig. 18. This figure is de- 



JEWELED BEARINGS FOR WATCHES. 



29 



signed to show what is meant by the angles formed by the 
lines of cleavage chipping off. It will be understood that 
the drawing exaggerates the condition. 

In some factories jewels are gauged and sorted out in a 
variety of thicknesses in order to facilitate the setting where 
automatic machinery is used for this purpose. 

Jewel Setting. — Where automatic machinery is used for 
setting jewels, the wire which forms the setting is usually 
fed out automatically and after the jewel is set the wire is 
cut off to the proper length; but where they are set by 
hand, the settings are previously prepared. The process of 
setting, being to all intents and purposes, identical in both 
cases, we shall describe the latter. 

In all American watch factories jewel settings are made 
on automatic machines. The shape of a jewel setting is 




Fig. 19. 



illustrated in Fig. 19. The object of having the hole at one 
side of a V shape is solely for the purpose of facilitating the 
subsequent process of stripping, by leaving less stock to be 
removed in the operation. In the process of setting, a step 
chuck is used. The setting is placed in this chuck with the 
Y opening toward the lathe spindle. Fig. 20. This figure 
shows a portion of the chuck holding the setting in position, 



3° 



JEWELED BEARINGS FOR WATCHES. 



the shape of the cutter and form of the recess made by it 
for the reception of the jewel. A is the chuck ; B, the jewel 
setting; C, the cutter. The jewel to be set is placed be- 
tween the jaws of a caliper rest, thus insuring the making 
of the recess of a proper diameter to fit the outside of the 
jewel. This is a very important matter for the reason that if 
a jewel does not completely fill the recess it is very likely, 








Fig. 20. 

when burnished in, to be out of center with its setting. This 
is to say, the jewel hole will not run true nor will the out- 
side diameter of the jewel. The disadvantage of this is that 
it necessitates shellac truing, which is a somewhat tedious 
operation and one requiring considerable skill. If the jewel 
is true and the hole central, it can be burnished into a setting, 
and the setting then trued up before removing from the 
chuck, the result being a perfectly true jewel and setting. 

Fig. 21 gives an enlarged view of a cutter for cutting the 
seat in a jewel setting, the jewel setting with the seat cut, 
and the jewel in place ready for burnishing. Pick the jewel 
up on the end of a finger slightly moistened and place it in 
the recess face out — we refer to a train jewel (bar hole). 
It is now ready for burnishing. Burnishing (or rubbing in) 
as it is called, is an operation requiring judgment and skill 



JEWELED BEARINGS FOR WATCHES. 



31 



which is only acquired by practice. The shape of the bur- 
nisher and the manner of presenting it are essential features 
to the success of this operation. 

In Fig. 22 we have endeavored to show in detail the man- 
ner of procedure. A is an edge view of the burnisher. B 
is a side view. C is a jewel setting with the jewel in place; 







op - view 



z*s& : 



Side 


i/iew 




^?''i 










'=&•* 



Fig. 21. 



the first operation of burnishing has been done, and the 
burnisher is in the exact position while doing the work. It 
will be observed that the burnisher has been forced into the 
brass of the setting a certain distance from the recess ; fur- 
ther that it has been forced down until its point has pene- 
trated to a distance equaling the depth of the recess in the 
setting. This has separated a portion of the stock from the 
main body except at the inner side. This little ring of metal 
is now to be laid over against the edge of the jewel. For 
this purpose cant the burnisher to one side as shown at D. 
The operation must be performed carefully in order to avoid 
cutting through the ring. The stock should be laid over 
slowly, gradually canting the burnisher during the proced- 
ure. The ring of stock is now in position for the final 
burnishing operation. This is represented at E. It will be 
seen that the upper part of the stock has been burnished 



32 



JEWELED BEARINGS FOR WATCHES. 



over close against the jewel. We have described the oper- 
ation of burnishing as well as we could and trust it will 
give the novice the correct idea as to the necessary manipu- 

A 



B 




Fig. 22. 

lation. It would be advisable for him to secure a few im- 
perfect jewels for the purpose of practicing the operation. 
All factories have, of necessity, more or less waste jewels 
which are of little value to them and could be readily secured 
at slight cost. Speaking for one of those factories, the 
South Bend Watch Factory of South Bend, Ind., we are 



JEWELED BEARINGS FOR WATCHES. 



33 




c 



Fig. 23 



34 



JEWELED BEARINGS FOR WATCHES. 



authorized to say that they will be supplied gratis upon 
request. 

The jewel having been burnished — rubbed in — the next 
operation is facing the setting — cutting the setting flat and 
true with the jewel. For this purpose use a cutter as at A, 
Fig. 23, passing it across the setting from the outside. This 
leaves a perfectly flat face coinciding with the face of the 
jewel. A cutter, as at B, is now passed over the edge as 
shown. The jewel when removed shows a setting with a 
slight rib, as at C. This rib, it will be understood, is the part 
held in the chuck. Now, it will be understood, that the re- 
cess in the setting and the outside of the setting run perfect- 
ly true with each other; therefore if the jewel has been set. 
true and the jewel hole is central with its outside, the jewel 
and setting as a whole is true, and it only remains to cut off 
the rim. This is a simple operation. Place the jewel in a 




Fig. 24. 

chuck — preferably a step chuck — and remove it by passing 
a cutter across or turning it off with a graver. 

The process for setting a balance jewel is mainly the 
same, the differences being that the bottom of the recess is 
flat, Fig. 24, and the face of the jewel — the cup side — rests 
against it, the burnishing being done against the convex 
side. 

Shellac Truing. — Shellac truing is a somewhat diffi- 
cult operation and is only used, when owing to imperfect 
setting or imperfectly centered jewels, the hole is not central 



EWELED BEARINGS FUR WATCHES. 



35 




Fig. 25. 



3& 



JEWELED BEARINGS FOR WATCHES. 



with the setting. In shellac truing the end of the taper is 
turned somewhat smaller than the jewel setting. The set- 
ting is cemented to it as shown in Fig. 25. Shellac is ap- 
plied to the end of the taper and the face of the setting 
brought in contact with it and the hole made to run true by 
inserting a point as at A, while the shellac is cooling. A 
shows a train jewel and B a balance jewel, giving the cor- 
rect position with regard to the end of the chuck. When 
the shellac is cool, a cutter passed over the edge will true 
up the setting. 




Fig. 26. 



It sometimes happens that a jewel, owing to an imperfect 
setting edge or to some other radical defect in the jewel 
itself, cannot be set so that its face will be perfectly flat 
with the setting. In such case it is better not to use the 
jewel; it can never be made a perfect job. If, however, it 
is absolutely necessary to use it, it can be to some extent 



JEWELED BEARINGS FOR WATCHES. 



37 



remedied as follows : Turn the end of the taper small enough 
to contact with the face of the jewel without touching- the 
setting. This is best accomplished by turning it with an ex- 
terior step as shown in Fig. 26. The object of turning it to 
this form is that it affords a better hold for the shellac than 




Fig. 27. 

if the taper were turned down to the diameter of the extreme 
end. This process is only practical for jewels having flat 
faces. There is too much uncertainty connected with the 
operation to make it advisable for balance jewels. The first 
method described, however, for shellac truing, is applicable 




Fig 



to all kinds of jewels having centrally located holes. When 
a shellac trued jewel has been previously inspected for 
finish, it requires no further inspection for centering. 

Jewel Fitting. — We have followed, throughout, the 
method of preparing the jewels and settings, to the point of 
applying them in the watch. We will now explain the 



3« 



JEWELED BEARINGS FOR WATCHES. 



method of selecting them to fit the parts, and of securing 
them in the watch plates. 

Of course the first operation is to select a jewel having 
a hole of the proper size to give a sufficient amount of side 
shake for the pivot. This selection of course is determined 
by the eye, but it will be found a great convenience to have 
your assortment of jewels gauged and kept consecutively in 
sizes. For this purpose, a needle gauge, which can be pur- 




Fig. 29. 

chased of watch tool dealers, is- the most convenient tool to 
use. -The principle of the instrument is that it is supplied 
with a slightly tapering part called a needle. This needle 
being inserted into the jewel hole determines the size by 
means of a point which is attached to the base of the needle, 
and is read on an index provided for the purpose. Some 
little skill and practice is required in the use of this gauge, 
especially if it is for gauging balance, or other small holes 
There is considerable danger of breaking the needle if not 
used very carefully. 

Figs. 27, 28 and 29 show the needle gauge and method 
of using it. Hold the gauge in the left hand with the thumb 
nail on the indicator point which slides along the index. 
Draw it down until the point of the needle projects slightly 



JEWELED BEARINGS FOR WATCHES. 39 

beyond the gauge as shown in Fig. 27. Take the jewel 
setting, or jewel in the tweezers as shown in the same figure. 
Insert the point of the needle into the jewel hole and slowly 
release the indicator point as shown in Fig. 27. Now draw 
the needle point down and with the tweezers press against 
the jewel, lightly, holding it against the end of gauge, release 
the needle. To remove the jewel from the needle after 
gauging, it is simply necessary to draw the indicator point 
back slowly, when the jewel will be released. 

Having selected a jewel which has the proper sized hole, 
the next operation is to set it in the plate. In some watches 
jewels are set directly in the plate. This is accomplished 
precisely the same as when set in a setting, so far as the op- 
eration of rubbing in is concerned. 

The watch plate is secured on the face plate of the lathe, 
the hole or location for the jewel being properly centered; 
the recess is made and the jewel then burnished in; ob- 
serving the same directions as apply to jewel settings. When 
a jewel thus set becomes broken, it must be replaced with a 
jewel having the same outside diameter, or else the recess 
should be sufficiently enlarged to take a jewel with a much 
larger diameter ; in fact, one with a diameter of sufficient di- 
mensions to allow the recess to be made for its reception 
beyond the rib, or depression, made in setting the other 
jewel. It will be seen, therefore, that it is much better, 
whenever practicable, to replace a jewel set directly in the 
plate by one set in a setting. 

In preparing the seat for the jewel secure the watch plate 
to the face plate of the lathe with its inner side toward the 
face plate as shown in Fig. 30. Center it up properly. The 
recess is then made for the jewel setting. It consists of two 
parts, the jewel seat shown at A, and the jewel body shown 
at B. It is best to have the jewel body portion as deep as 
possible in order to give stability to the jewel. The seat 
need only be of slight depth. One one-hundredth of an inch 
is usually quite sufficient. 



40 



JEWELED BEARINGS FOR WATCHES. 



The jewel setting has two parts called the pipe and the 
body. The pipe is the smaller portion shown at A, Fig. 31. 
The jewel body is the larger portion shown at B. The por- 
tion B, Fig. 31, should be a good fit for the plate portion B, 
Fig. 30. The pipe need not be a fit for the plate portion A. 
It is now necessary to provide the proper endshake for the 
pinion or arbor being jeweled. Let us assume that the jewel 
being fitted is in the lower plate. Place the pinion or arbor 
with its upper pivot in the top plate, lower side uppermost; 
invert the lower plate and put it in place with the lower end 



F'~- '"" 







$ 



*-*£ 



Fig. 30. 

of the staff projecting into the recess made for the new 
jewel setting. Screw the plates together. Push the new 
jewel into place and try the end-shake. It will be seen that 
it is always best to cut the shoulder, or pipe, on the setting 
shorter than required in order that the end-shake when first 
tried may be too great, rather than too little. Assuming that 
it is too great on first trial, hold the jewel with its setting in 
a spring chuck and turn the shoulder back a trifle, repeating 
this until the correct endshake is secured. 



JEWELED BEARINGS FOR WATCHES. 



41 



Side-Shakes and End-Shakes. — The measurements 
given are metric and are expressed in millimeters. Thus, 
.015 mm. is one and a half hundredths of a millimeter, .007 
mm. is seven-thousandths, or nearly three-quarters of a hun- 
dredth of a millimeter. 

For the convenience of those who may not be thoroughly 
conversant with metric measurement let it be understood 
that it requires, practically, two and a half hundredths of a 
millimeter to equal one-thousandth of an inch. To convert 
millimeters into inches multiply by .03937. Thus, two and a 



A 



£ 




Fig. 31. 

half hundredths of a millimeter, expressed .025 mm., multi- 
plied by .03937, gives .00098425 inches. 

The side-shakes and end-shakes given below are the re- 
sult of repeated tests and careful observation covering a 
period of more than half a century and will be found to give 
excellent results. 

In determining the proper side-shake and end-shake to 
give to any member of a watch train or escapement the 
shape of the jewel holes, the shape of the pivots and even 
the material of which the jewels are composed exercise an 



4 2 



JEWELED BEARINGS FOR WATCHES. 



influence. A straight hole requires more side-shake than an 
olive hole. A cone pivot may be fitted with much less side- 
shake and end-shake than a straight pivot. This is to say, 
a pivot that is end-shook against its shoulders. A garnet or 
other soft jewel cannot safely be fitted as closely as a ruby 
or sapphire. 

For all pocket watches, down to and including 12 size, the 
center, third and fourth may have .015 mm. side-shake and 
.04 mm. end-shake ; the escape .01 mm. side-shake and .035 




SetttM.1 




Fig 



mm. end-shake ; the pallet arbor .007 mm. side-shake and 
.035 mm. end-shake ; the balance .003 mm. side-shake and .02 
mm. end-shake. 

For sizes 10 and below: Center, third and fourth, .015 
mm. side-shake and .035 mm. end-shake ; the escape, .009 
mm. side-shake and .035 mm. end-shake ; the pallet arbor, 
.006 mm. side-shake and .03 mm. end-shake ; the balance, 
.003 mm. side-shake and .02 mm. end-shake. 



JEWELED BEARINGS FOR WATCHES. 43 

For 19 and 21-jeweled watches where escape and pallet 
arbors are jeweled in olive holes the side-shakes may safely 
be made as close as the balance. 

It may sometimes happen that in attempting to get the 
end-shake the shoulder may be turned back a little too much. 
This is sometimes remedied by holding the setting in a 
spring chuck and throwing up a slight burr on the edge of 
the shoulder with the pressure of a burnisher against it. 
This, however, is not to be recommended, being at best a 
makeshift, not a strictly workmanlike job. The outer end 
of the setting is now turned down slightly below the surface 
of the watch plate and its outer edge slightly chamfered, or 
brought to a taper as shown in Fig. 32 ; then the plate is 
burnished over to hold it, exactly as though it were a naked 
jewel being burnished into a setting. 

In fitting a setting to a top plate proceed in the same man- 
ner up to the point where the end-shake is secured. Settings 
are sometimes put in by the method known technically as 
"frictioned in." This frictioning is sometimes done from 
the top side and sometimes from the lower side. I would 
advise against adopting this method except in case of dire 
necessity, and by all means never friction in from the top. 
The reason for this advice is that when a jewel is frictioned 
from the bottom there is at least no danger of its dropping 
out of the plate, which is not the case when frictioned from 
the top ; but the disadvantage in both cases is that there is no 
certainty of the end-shake remaining permanently correct. 

The only secure method of fastening in a jewel and set- 
ting which is desired to be removable from a plate, is to use 
two or more screws. We will now proceed to describe the 
method of accomplishing this. First we will describe the 
method of providing for securing the jew T el where it has 
not previously been fitted in this manner. The first opera- 
tion is to drill and tap two holes, diametrically opposite as 
to the jewel setting. These holes should be as near as pos- 
sible to the recess without clanger of bulging inward. In 
fact, it is better to make them before the recess in the plate 



44 



JEWELED BEARINGS FOR WATCHES. 



is opened to its full size. This for the reason that the tap 
is less liable to bulge the wall out into the recess. The jewel 
being fitted is turned down almost flush with the upper side 
of the plate — say within i/iooo of an inch — and one jewel 
screw brought to place with its head resting on the plate and 
projecting over the edge of the setting. This single screw 
will serve to hold the setting in place while counterboring 
the opposite hole for the screw head. Of course if the 
screw heads are to be left above the setting, this counter- 
boring will not be done. 






Side 


view 


^T~^~ - 


_\^~ 









£/7iCt view 



Fig. 33 A B. 

There are two kinds of counterbores used for making re- 
cesses for jewel screwheads. One is known as the two- 
lipped and the other may be called the multiple tooth. A 
two-lipped counterbore is shown at Fig. 33. It needs no 
further explanation. Such counterbores may be bought of 
watch tool dealers or can be very easily made. In making a 
counterbore of this kind select a piece of steel wire of the 
size required for the recess. If this is not at hand select a 
piece somewhat larger in diameter; then turn down one 
end to the proper size ; turn the point to a diameter that 
will just fill, without binding, the tapped hole for the screw. 
Now file two sides flat and parallel, as shown by the end 
view, A, Fig. 33. In backing off the lips the backing off 
should be carried around the tip of the counterbore, as 
shown at B. This counterbore is onlv suitable in cases 



JEWELED BEARINGS FOR WATCHES. 



45 



where there is no counterbore already in the plate ; this is to 
say, where no screwed in jewel has previously been used. 
The multiple tooth counterbore is the proper form to use in 
replacing a jewel having a screwed in setting. This form 
of counterbore is shown in Fig. 34. In this figure, A is an 
erd view, B a side view and C a view showing the position 
in which the file should be held in making the teeth. A 
counterbore of this form possesses the advantage that one or 




Fig. 34 a b c. 

more teeth are always in action on the setting. Another ad- 
vantage is that the cutting edge of the tooth is radial. The 
method of making this counterbore is as follows : Proceed 
as in the case of the lipped counterbore, to turn the outside 
diameter the required size for the jewel screw head; drill a 
hole in the end, of the exact size for the tit ; shape the teeth 
with a three-cornered or beveled edge file as shown at C ; 
harden the counterbore; turn up and fit the pilot, or tit; 
finally fit a suitable handle. In order that the screw head 
may hold the setting down to its place, the edge of a coun- 
terbore of this sort should be so shaped that it will cut a re- 



46 JEWELED BEARINGS FOR WATCHES. 

cess slightly deeper at the center than at the outside ; or at 
least it must not be deepest at the outside. The object of this 
precaution should be obvious. In order that a screw head 
may hold the setting down firmly to place the edge of the 
setting should be at least as high as any other part of the 
bottom of the recess. 

In recessing for the jewel screw proceed as follows: The 
jewel being held in place by one screw, as previously de- 
scribed, insert the pilot of the counterbore in the hole at the 
opposite side and cut down the setting to the depth required. 





Pig, 35. 

Now insert a screw into the recess just made and screw it in, 
to hold the setting; remove the screw first put in, cut the 
setting on that side and replace the screw. The operation is 
now complete so far as fitting the jewel is concerned. 

Stripping and Polishing. — The technical term, ''strip- 
ping," is applied to the beveled portion of the setting, wheth- 
er this beveled portion be on a top plate, or a lower plate 
setting, or whether it be on the plate itself, where the jewel 
is rubbed directly into the plate. It is not usual to polish 
these bevels, except in the top plate. Balance jewel settings 



JEWELED BEARINGS EOR WATCHES. 



4/ 



are sometimes polished. Train jewels in the lower plate are 
seldom polished. 

The operation of stripping is a delicate one, requiring 
some practice. The stripping bevel is made in two different 
forms, known as straight bevel and concave bevel. Fig. 35 
shows the two forms, A being the straight, B the concave. 
The form selected is entirely a matter of choice. The bevel 
should first be formed with an ordinary graver. This is 
called rough stripping. It is then finished, either with a 
sapphire stripping tool, or a polished graver. In watch fac- 
tories the finished stripping is generally done with a sapphire 
tool. The form of this tool is shown in Fig. 36. The method 




/ — - ^ 


^—---4- — MS3M.- 1 — — 


a/ "^ r ~- 


■^ 


\ 


tz. ^"".r'-^^gS. 




Fig. 36. 

of making this tool is first to grind the sapphire strip to the 
proper shape, using a soft steel or copper lap charged with 
No. 1 diamond powder. These sapphire strips may be pur- 
chased in the rough. After bringing the cutter to form, it is 
then polished with a boxwood, or other hard wood, lap 
charged with No. 4 diamond powder. By finally finishing 
with No. 5 a very superior edge will be obtained. In the 
use of this cutter a good deal depends upon the manner in 
which it is presented to the work. The clearance edge 
should be held as nearly parallel with the bevel as possible. 

Referring to Fig. 36, A is a top view ; B a side view ; 
a is the face ; b the clearance, and c the undercut. It will be 
observed that the clearance edge b is slightly circular and 



4 8 



JEWELED BEARINGS FOR WATCHES. 



forms but a slight angle with the face, a. This is essential 
for perfect work. 

Where a concave bevel is desired, the point of the tool 
should be slightly curved. 

The use of the sapphire stripper requires a great deal of 
practice, and is not to be advised except where the replacing 
of jewels is so frequent that the workman is enabled to keep 
up this practice. Almost as good results may be secured 
with a polished steel graver, and much more readily. To 




Block *s= 



Fig. 37. 

prepare this graver it should first be sharpened on an oil 
stone, observing the same care in shaping the clearance 
edge as in the case of the sapphire cutter. After sharpening 
to form, it should be polished on a boxwood or other close- 
grained, hard wood block, using Vienna lime and alcohol, 
or diamantine and oil ; the former is the quickest and best. 
Fig. 37 shows how a graver should be presented to the 
block while being polished. A shows the position while 
polishing the face and B the position while polishing the 
clearance edge. The graver should be drawn from the cut- 
ting edge, as indicated by arrows, and the lines broken bv a 
side-way motion. The same directions are applicable to the 
clearance edges. Instead of using a flat block, a hard wood 
lap may be used. 

The polished graver described will not leave the finish of 
the bevel perfect. This may be done with a peg-wood point 



JEWELED BEARINGS FOR WATCHES. 



49 



as shown in Fig, 38. This point is first dipped in alcohol 
and then in Vienna lime brought to impalpable powder. A 
and B indicate the shape of the peg-wood point. A gives 
^1 




B 




Fig. 38. 

a side view and B an edge view. A is the position in which 
it is held while polishing the bevel. 

In using the stripping tool, the polished graver, or the 
peg-wood polisher, care should be exercised that they be 
not held in one position during the operation. Constant 
motion is required in order to produce a perfect polish, and 
a freedom from lines. This is to say, the tools should first 
be brought with their points almost in contact with the jewel, 
then drawn slowly outward. Care should be exercised to 
avoid actually touching the jewel with the stripper, or the 



50 JEWELED BEARINGS FOR WATCHES. 

polished graver, either of which would be likely to scratch it ; 
but the peg-wood polisher can do no harm. A little prac- 
tice will enable the workman to acquire the necessary skill 
and produce a nice job of stripping. 

The final operation is that of polishing the face of the 
jewel setting. This is very easily done when the appliances 
are in good order ; otherwise it is impossible to produce 
good work. The requisite appliances are a fine piece of 
"water of Ayr," or "Tarn O'Shanter" stone of any con- 
venient size or shape; the ordinary i-inch square slip will 
answer. A piece of Jasper, not less than 2]/ 2 inches in diam- 
eter, and a piece of Agate of the same size, or larger. The 
preparation of these stones is not extremely difficult, but 
requires care and patience. The Water of Ayr stone is 
brought to a fine surface by rubbing on a cast iron block. 
Do not use emery or any other abrasive material on the 
block, for the reason that it would be likely to penetrate the 
grain of the stone, with the result that the setting would not 
be free from scratches. 

The method of preparing the surfaces of the Jasper and 
of the Agate are similar. These stones are found in the 
market already prepared with a flat surface, but not in con- 
dition to produce good work in polishing settings. The 
manner of procedure to bring the surface in proper condi- 
tion is as follows : 

Take a cast iron block of not less than six inches in diam- 
eter ; have the surface planed perfectly flat and as smooth 
as possible, place upon the block a small quantity of very 
fine carborundum, or corundum mixed with oil — the former 
is best for the purpose. Either of these compounds should 
be of fine and uniform texture. This condition may be se- 
cured by settling, as in preparing diamond powder. The 
stone to be prepared should be rubbed on this block with a 
circular motion and a comparatively light pressure, until a 
perfectly true surface is secured on the stone. Now, the 
stone and block should be washed and wiped dry and the 
rubbing continued without any of the abrasive compound. 



JEWELED BEARINGS FOR WATCHES. 5 1 

A repetition of these operations is desirable where the best 
results are expected. The last operation should be con- 
tinued until the surface of the stone has a glassy appearance. 

The final operation is known as charging the stone, for 
which purpose diamond powder is used. The term "charg- 
ing the stone" is used in connection with the assumption 
that the grains of diamond powder are actually driven into 
the grain of the stone, but this is a matter of dispute which 
never has been definitely settled. However that may be, 
diamond is the only substance that has been found satisfac- 
tory. In charging the stone, a small piece of agate with 
a flat surface is used. This is called the charging stone, and 
is usually about an inch and a half in diameter. Its surface 
should be prepared by the same process as described for 
the larger jasper and agate stones. 

For charging, use the finest settled diamond powder pro- 
curable. This may be obtained from the oil used in set- 
tling, as follows : After the No. 5 diamond powder has 
been procured by settling for 24 hours, allow it again to 
settle for at least five days ; the residue thus obtained will 
be found excellent for the purpose of charging. Place a 
small quantity of this powder on the stone to be charged 
and rub with a small circular motion and light pressure of 
the charging stone. The result will be a beautiful, almost 
polished, surface. Now wash the stones thoroughly with 
grain alcohol and they are ready for use. In using them 
.proceed as follows : Rub the face of the setting on the 
Water of Ayr; wash thoroughly and rub first on the jasper, 
then on the agate. If the stones have been put in proper 
condition a very few rubs will suffice. All these operations 
should be performed with a slight circular motion. For the 
final finish on the agate a heavy pressure is first, used, grad- 
ually becoming lighter and lighter. ' In polishing, the bare 
finger should not be allowed to come in contact with the 
face of the stone. Fabric of some sort should be interposed. 
A finger-cot made of canton flannel, nap side towards the 
finger, is convenient to use for this purpose. 



52 



JEWELED BEARINGS FOR WATCHES. 



The stones used for polishing and that for charging 
should be taken great care of. Dust should be excluded, and 
they should be thoroughly washed with alcohol before using. 

The author has gone into the various operations connected 
with jewel making, opening, setting and finishing, with con- 
siderable detail. In case anything in the above is not clear 
to the reader, or if further information on the subject is 
desired, a letter to the publisher will bring a prompt reply. 

The shape of the balance jewel hole is of the first impor- 
tance. The best results cannot be obtained where a hole 
having parallel sides is used for the reason that a very slight 
thickening of the oil will impede the motion of the balance 
unduly. 




Fig\ 39. 



They should be what is known as olive holes as repre- 
sented in Fig. 39. This shape reduces the retarding effect 
of thickening oil to the minimum. The face of the jewel 
should have a hemispherical oil cup and the back should be 
well rounded. When in position, the distance between the 
jewel and the endstone should be about two hundredths of 
a millimeter. If this distance is too great the jewel will soon 
become dry for a reason which I will explain a little later on. 
It is a very bad practice to allow the jewel and endstone 
to be in actual contact, as you will sometimes find in the 



JEWELED BEARINGS FOR WATCHES. 53 

cheapest foreign work. This prevents the oil flowing freely 
about the end of the balance pivot, where it is most needed. 
The advantage of having the back of the balance jewel well 
rounded and at a slight distance from the endstone is that 
the balance pivot will by this means be supplied with oil 
from capillary attraction. 




If the upper side of a balance jewel be flat, as shown in 
Fig. 40, the greater portion of the oil will be drawn between 
the settings, leaving the pivots dry, whereas, if the jewel 
be well rounded, the oil will collect at the center and the 
balance pivots be kept lubricated until the last particle of oil 
is exhausted. 



MA R 8 1912 



